1Department of Veterinary Microbiology and Preventative Medicine, College of Veterinary Medicine, Iowa State University, 2MRC Centre for Inflammation Research, University of Edinburgh, 3Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University

1Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, 2Department of Bioengineering and Orthopaedic Surgery, University of Pittsburgh, 3Research Laboratory of Electronics and Department of Biological Engineering, Massachusetts Institute of Technology, 4MRC Centre for Regenerative Medicine, University of Edinburgh, 5Stem Cell Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, 6Department of Orthopaedic Surgery, University of Texas Health Science Center at Houston, 7Department of Orthopaedic Surgery, UCLA Orthopaedic Hospital, David Geffen School of Medicine, University of California at Los Angeles